import java.util.Scanner;

public class Ex2_22{
	public static void main(String[] args){
		Scanner input = new Scanner(System.in);
		System.out.print("Enter the side: ");
		double side = input.nextDouble();
		double area = 3.0 / 2 * Math.pow(3, 0.5) * side *side;
		System.out.println("The area of the hexagon is " + area);
	}
}